This example builds an animated face entirely with D3.js v5, using SVG shapes for the head, eyes, eyebrows, and mouth. The code calls `d3.arc()` to trace the mouth’s curved path, while `transition().duration()` animates the eyebrows upward and back over two seconds. A yellow circle forms the face with black strokes, and fixed pixel constants position each facial feature symmetrically around the SVG’s center.